Radiation resistance and chemical stability of yttrium aluminum garnet

Abstract

The radiation resistance and chemical stability of yttrium aluminum garnet doped with short-lived ²⁴⁴Cm for accelerated accumulation of radiation damages was studied. Two garnet samples of the stoichiometry Y_2.8853Cm_0.1024Pu_0.0092Al₅O₁₂, containing ∼4 wt % Cm with 70% content of ²⁴⁴Cm, were synthesized. The ceramics consist of the target phase of the garnet structure and a small amount of corundum. The chemical stability of the freshly prepared sample in water was studied (MCC-1 test, 90°C). The Cm leach rate is ∼10⁻² g m⁻² day⁻¹, and that of Al and Y, ∼10⁻³ g m⁻² day⁻¹. The garnet became fully X-ray amorphous owing to self-irradiation in 530 days at the accumulated dose of 4.0 × 10¹⁸ α-disintegrations per gram, or 0.3 displacement per atom. After the destruction of the garnet structure, the Cs leach rate from the matrix 14 days after the start of the experiment increased by a factor of 10, and that of Y, by a factor of 60 relative to the freshly prepared ceramics.